1. Field of the Invention
This invention relates to the non-invasive determination of blood flow.
2. Description of the Prior Art
In medical practice it is often essential that the pattern of blood flow be determined quickly and accurately for example, in trauma where a limb may have been reattached, the assessment of pressure sores, plastic surgery for monitoring graft viability and in peripheral vascular diseases. When amputation is likely it is important that the extent of blood flow be known.
Various techniques for blood flow determination have been proposed. One publication, "Blood Flow Measurement: Future Applications and Prospects", Robert F. Rushmer, Medical Instrumentation Vol. 11 No. 3 May-June 1977, mentions the laser-Doppler method in which a optical-Fiber directs light from a laser at the superficial vessels of the skin and reflected light indicates blood flow in these vessels. A much more recent publication, "Limb Pertusion in the Lower Limb Amputee", S.L.E. Fairs et al., Prosthetics and Orthotics International, 1987, Vol. 11 80-84, refers to the use and value of the optical-Fiber instrument but mentions problems resulting from the movement of the optical-Fiber, which has to be close to the surface of the area being examined.